Lightweight panel construction

ABSTRACT

A lightweight panel construction in which a thin layer or veneer of gypsum board is laminated as a facing sheet onto a backing of lightweight open cell reinforcing material to form a composite panel that has the same surface characteristics and appearance as a sheet of conventional gypsum board and is suitable as a lightweight but strong substitute for conventional gypsum board. Portions of the open cell reinforcing material may be removed or omitted to form raceways or channels for utilities or the like.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates generally to building materials. Morespecifically, the invention relates to a lightweight panel constructionthat is suitable as a substitute or alternative for conventional gypsumwallboard.

[0003] 2. Prior Art

[0004] The interior framing of residential and commercial buildings istypically covered or finished with sheets of gypsum board, commonlyreferred to as drywall, wallboard or Shertrock® (trademark of U.S.Gypsum Company). Conventional gypsum wallboard has a gypsum plaster corefaced with sheets of paper, and normally is made in standard size panelswith dimensions of 4×8, 4×12 or 4×16 feet, and thicknesses ranging from⅜ inch up to ¾ inch, although thicknesses as little as ¼ inch can beobtained by special order for specialized use.

[0005] Considerable transportation costs, and difficulty in handling andinstallation are associated with conventional gypsum wallboard becauseof its density and weight. Moreover, gypsum wallboard is susceptible tomoisture damage, and is easily dented or broken if struck near the edgesor corners. Further, relatively expensive landfill costs are associatedwith disposal of conventional gypsum board.

[0006] Alternatives to conventional gypsum wallboard have been proposed,including wood particle board, and lightweight materials such as paperfiber, composites of synthetic materials, and/or honeycomb reinforcingstructures faced with various materials, including plaster orconventional sheets of gypsum board.

[0007] U.S. Pat. No. 3,106,503, for example, discloses a compositewallboard having a paper honeycomb core which can be faced on one orboth sides with commercially available conventional sheets of gypsumboard. The principal object of this patent is to provide a structuralpanel that can withstand direct contact with flame, and which may bemoisture resistant. Further, a stated object is also to provide alightweight structural panel that has superior qualities of rigidity andstrength. However, commercially available sheets of gypsum board havingconventional thickness, i.e., from ⅜ inch up to ¾ inch, are applied tothe honeycomb core. The panels described in this patent are thereforerelatively heavy and hard to handle in that they still incorporatesheets of gypsum board having conventional thickness, and the compositepanel appears to have a total thickness substantially greater than thethickness of conventional gypsum board. Further, manufacture of thepanels described in this patent is relatively complicated and expensive.

[0008] U.S. Pat. No. 3,170,827 discloses a method of making aninsulation panel having facing sheets of asbestos cement board separatedby approximately six inches of polyurethane foam reinforced withhoneycomb paper. In making the panel, a layer of foam-forming chemicalsis deposited on a bottom facing sheet, a honeycomb structure is pressedinto the chemical layer into bonding relationship with the bottom facingsheet, the foam is expanded, and a top facing sheet is placed on top ofthe structure, in contact with the expanded foam, which bonds thecomponents together.

[0009] U.S. Pat. No. 3,246,058 discloses a method for producingreinforced foam laminate structures, wherein a reinforcement member,e.g., corrugated material, is fed between two continuously suppliedspaced sheets of facing material, at least one of which has been coatedwith an organic foam material, and the foam is expanded to fill thespace and bond the components together.

[0010] U.S Pat. No. 3,249,659 discloses a method of making structuralpanels useful as walls, partitions, doors, truck bodies and the like,wherein a core is interposed between facing sheets and partially filledwith a foamed plastic to form an air space therein. In particular, alayer of foam-forming mixture is applied to the inner surfaces of thefacing sheets, a reinforcing member is inserted between the sheets, andthe layers of foam-forming mixture are expanded toward one another butwithout merging. A structure analogous to an I-beam is thus formed.

[0011] U.S. Pat. No. 4,351,870 discloses a panel construction especiallysuitable for earthquake and fire resistance, and adapted for assembly ofpre-fabricated components to form a building. The panel includes one ormore layers of strength-increasing material separated by lower strengthbulk-producing layers which may comprise foamed plastic or foam rubbermaterials. Facing sheets such as wood veneer, plastic simulated woodveneer, wallpaper finish, brick, tile, or plaster may be used to obtaina desired appearance.

[0012] U.S. Pat. No. 4,917,742 discloses a method of making lightweightbuilding panels having a foam-filled honeycomb core faced withfiberglass-reinforced plastic sheets.

[0013] U.S. Pat. No. 5,309,690 discloses a lightweight composite panelintended as a substitute for gypsum board. The panel comprises acellular core filled with an inorganic insulating material and amaterial which releases water at elevated temperatures, and first andsecond sheets such as corrugated cardboard bonded to opposite sides ofthe core.

[0014] U.S. Pat. No. 5,338,594 discloses a lightweight insulation andstructural material for building and aerospace industries, wherein ahoneycomb structure is filled with a polycyanurate foam. The foam isexpanded in the honeycomb cells while contained by pressure plates aboveand below the cells.

[0015] U.S. Pat. No. 5,679,433 discloses a non-combustible walldecorating panel having a honeycomb core and a metal foil facing sheet.

[0016] Although the prior art discloses a variety of panels, some ofwhich have good strength-to-weight ratios, including panels suitable foruse in the building industry, it does not disclose any lightweight andtough panel intended as a substitute for conventional gypsum board wallpanels, wherein the substitute panel has the same surfacecharacteristics as conventional gypsum board panels, i.e., it has asurface veneer of paper-covered gypsum plaster, and preferably has thesame dimensional relationships, whereby the panel may be installed andfinished using conventional techniques and equipment.

[0017] Accordingly, there is need for a panel that has the same surfacecharacteristics as a conventional gypsum board, and has the samedimensional relationships, but is substantially lighter in weight whileat the same time possessing superior toughness.

SUMMARY OF THE INVENTION

[0018] The invention is a composite panel for use in place ofconventional gypsum board panels, and that has the same surfacecharacteristics and preferably the same dimensional relationships as aconventional gypsum board panel, but is significantly lighter in weightwhile at the same time possessing superior toughness.

[0019] The panel of the invention is an improvement over conventionaldrywall or gypsum board primarily because of its greatly reduceddensity, which results in a weight reduction of sixty or percent orgreater, and the benefits associated with this reduced density. Thesebenefits include reduced transportation costs and requirements, reducedlabor for handling and installation, less dust and debris when workingwith the panel, improved workability and elimination or reduction oflandfill fees required for disposal, and potentially a reduction ofstructural members that would otherwise be required in a building simplyto support the considerable weight of conventional gypsum board.

[0020] The panel of the invention comprises an open cell reinforcingcore structure faced with a thin gypsum board veneer, and has a greatlyimproved strength-to-weight ratio compared with conventional gypsumboard panels, especially when it employs a foam-filled coreconstruction, being synergistically stronger than either the open cellcore structure or the gypsum board alone.

[0021] One open cell core construction suitable for use in the inventionis the Hexacomb_(tm) packaging material made by Pactive Corporation(formerly Tenneco). This packaging material is a paper honeycombstructure, and in one embodiment comprises strips of 33 lb. liner gluedtogether at contact lines running in the machine direction. Each stripof core paper is aligned such that the machine direction is in thethickness direction of the core. The primary fibers are thus alignedwith the machine direction, resulting in the greatest compressionstrength and stiffness.

[0022] A gypsum board facing sheet or veneer is applied to at least oneside of the core, to provide the same surface characteristics andappearance as conventional gypsum board. This facing sheet is only deepor thick enough to obtain these characteristics, i.e., to enable normalworking of the panel, namely, sanding, cutting, finishing and acceptanceof fasteners, in the same way as obtained with conventional sheets ofgypsum board. A suitable thickness for the gypsum facing sheet or veneerwould be in the range of from about {fraction (1/16)} of an inch up toabout ⅛ of an inch, or even up to ¼ of an inch.

[0023] For example, to produce a panel having a standard nominalthickness of ½ inch, a facing sheet of ⅛ inch thickness could be appliedto a honeycomb core having a thickness of ⅜ inch; or, a facing sheet of{fraction (1/16)} inch thickness could be applied to a honeycomb corehaving a thickness of {fraction (7/16)} of an inch; etcetera. Similarly,to produce a panel having a ¾ inch thickness, the facing sheet could beonly ⅛ inch thick, but the core thickness would be increased to ⅝ inch;or alternatively, a thinner facing sheet, e.g., {fraction (1/16)} inch,could be applied to a core having a thickness of {fraction (11/16)} ofan inch. It should be understood that the gypsum facing sheet could haveother thicknesses, as long as it is thick enough to impart the desiredsurface characteristics to the panel, but not so thick as tounnecessarily increase the weight of the panel. Thickness of from about{fraction (1/16)} of an inch up to about ¼ inch, for example, may besuitable.

[0024] A panel constructed in accordance with the invention is strongernear the edges and corners than a conventional gypsum board, because thefoam-filled core material does not break and crumble near the edges aswill conventional gypsum board. It is also anticipated that theinstallation or addition of electronic circuitry will be easier thanwith conventional gypsum board. For instance, circuitry can be embeddedin the cells of the core, in the facing, or between the cells andfacing, which can facilitate construction of the “house of the future”.For example, sensors which can track the location of specific objects orpersons, monitor and control climate settings, record events, etc., canbe incorporated into the structure. Moreover, portions of the core maybe left open to provide raceways or channels for utilities or the like.

[0025] The core material can be paper-based or other material such asplastic or a composite. If paper-based, the core material can bebleached or unbleached, virgin or recycled, or a combination thereof,and can be impregnated or coated with a suitable resin or other materialselected for its desired properties. The core construction can be eitherhoneycomb, corrugated, or laminations of corrugated layers orcombinations of corrugated and honeycomb. If a honeycomb coreconstruction is used, the cell size can typically vary from ⅜ inch to 1inch center-to-center, although other dimensions can be employed. Thefoam used to fill the core can be a fire rated or fire retardant foam,or a foam having other desirable properties, and can be selected fromany of those commercially available, for example.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The foregoing, as well as other objects and advantages of theinvention, will become apparent from the following detailed descriptionwhen considered in conjunction with the accompanying drawings, whereinlike reference characters designate like parts throughout the severalviews, and wherein:

[0027]FIG. 1 is a top perspective view showing panels according to theinvention installed in place on a wall frame structure;

[0028]FIG. 2 is a fragmentary, enlarged, transverse sectional view of apanel constructed in accordance with the invention;

[0029]FIG. 3 is an enlarged, fragmentary, top perspective view, withportions broken away, of a portion of a panel in accordance with theinvention;

[0030]FIG. 4 is a further enlarged, fragmentary perspective view insection of a panel in accordance with the invention;

[0031]FIG. 5 is an exploded top perspective view showing the majorcomponents, and their arrangement, in a panel according to theinvention;

[0032]FIG. 6 is a somewhat schematic top perspective view showing stripsof paper glued together in the preparation of a honeycomb core materialfor use in the invention;

[0033]FIG. 7 is a top perspective view of the secured-together strips ofpaper after the cells are expanded in the “x” and “y” directions;

[0034]FIG. 8 depicts a strip of paper with the fibers aligned in themachine direction;

[0035]FIG. 9 is a top perspective view of a piece of corrugated materialwhich may be used to form the open cell reinforcing structure in thepanel of the invention;

[0036]FIG. 10 is an enlarged transverse sectional view of a portion of apanel according to the invention, showing a corrugated open cellreinforcing core structure faced with a gypsum board veneer and whereinthe cells of the core are filled with an expanded foam;

[0037]FIG. 11 is an exploded perspective view showing a plurality ofsheets of corrugated material that may be laminated together to form theopen cell reinforcing core in the panel of the invention; and

[0038]FIG. 12 is an exploded perspective view showing a plurality oflayers or laminations of corrugated and honeycomb material disposed inanother possible arrangement for forming the reinforcing core.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] Referring more specifically to the drawings, a lightweight panelin accordance with the invention is indicated generally at 10 in FIGS.1-5.

[0040] In FIG. 1 a plurality of panels 10 are shown secured in aconventional manner to a frame structure F, i.e., the panels areattached or “hung” in the usual manner, typically with the longdimension extending horizontally and with joints offset. Screws or othersuitable fasteners 11 are extended through the panels into the frame. Inthis regard, the panels 10 are installed and worked exactly the same wayas conventional gypsum wallboard, except that they are much lighter andeasier to handle.

[0041] With particular reference to FIGS. 2-4, the panel 10 comprises alightweight open cell reinforcing structure 12 having secured on oneside thereof a gypsum board facing sheet 13, and on the other side abacking sheet 14.

[0042] In a preferred embodiment, the open cell reinforcing structurecomprises a honeycomb core filled with a polyurethane foam 15. The foamadds strength and rigidity to the panel while also serving topermanently bond the components together.

[0043]FIG. 3 depicts a form in which the foam is omitted, and the panel10′ comprises just the honeycomb core 12, backing sheet 14 and gypsumfacing sheet 13.

[0044] The backing sheet 14 and honeycomb core may both be made of papermaterial, e.g., kraft paper or liner, either bleached or unbleached, andthe gypsum board facing sheet 13 may be conventionally constructedexcept that it is very thin, e.g., on the order of {fraction (1/16)} to¼ of an inch thick. Thus, as shown in FIG. 4, the gypsum board facingsheet has a gypsum plaster core 16 between paper skins 17 and 18.Additionally, the long side edges of the sheet 13 may be slightlytapered on the face of the sheet as indicated at 19 in FIG. 1 tofacilitate taping and hiding the joint between adjacent panels, just asin a conventional gypsum board. Further, the thickness of the facingsheet 13 is just sufficient to enable the fasteners 11 to dimple thesurface of the sheet, leaving a shallow depression that can be filledwith joint compound during finishing of the wall surface, thereby hidingthe fasteners and providing a smooth surface.

[0045] The panel 10 may be made in standard sizes, e.g., 4×8 feet, 4×12feet, or 4×16 feet, with thicknesses ranging from ⅜ of an inch up to ¾of an inch or greater. In each instance, the facing sheet 13 of gypsumboard is only thick enough to provide the appearance and surfacecharacteristics of a conventional gypsum board, e.g., about {fraction(1/16)} to ¼ of an inch thick. Thus, for example, for a panel 10 havingan overall thickness of ⅜ of an inch, and a facing sheet of gypsum boardhaving a thickness of {fraction (1/16)} of an inch, the core would havea thickness of about {fraction (5/16)} of an inch. For a panel having anoverall thickness of ¾ of an inch, and a facing sheet having a thicknessof {fraction (1/16)} of an inch, the core would have a thickness ofabout {fraction (11/16)} of an inch.

[0046] The use of a very thin gypsum board facing sheet on a reinforcingcore or backing provides a very lightweight and strong panel that hasthe same appearance and workability as a conventional gypsum board, butis substantially lighter and easier to handle.

[0047] The panel may be manufactured in a variety of ways. According toone way, shown in FIG. 5, a thin layer 20 of foamable material is laidon top of backing sheet 14. A honeycomb structure 12 is then pressedinto the layer of foamable material, and a facing sheet 13 of very thingypsum board is placed on top of the honeycomb structure. The foamablematerial is then caused to expand, filling the cells of the honeycombcore and contacting the facing sheet. Upon being cured, the foam bondsall of the components together to form a composite structure having highcompressive strength and rigidity. This manufacturing method may becarried out by machine in a continuous process.

[0048] FIGS. 6-8 depict one method by which the paper honeycomb core canbe made. According to this method, strips 25 of paper are glued togetherat spaced areas 26 to form a convoluted structure, which is thenstretched out primarily in the direction of the arrow 28 to form aplurality of hexagonal cells 29. The paper is arranged so that theprincipal fibers are parallel to the machine direction MD. The resultantstructure has great compressive strength and rigidity.

[0049] In a preferred construction, the Hexacomb_(tm) packaging materialmade by Pactive Corporation is used for the honeycomb core. Thismaterial uses 33 lb. paper strips. The cell size of the honeycomb matrixpreferably is from ⅜ of an inch to 1 inch, center-to-center. Thethickness varies depending upon the desired finished thickness of thepanel.

[0050] An alternative material for forming the reinforcing structure isdepicted in FIGS. 9 and 10. Rather than the honeycomb structure, a sheetof corrugated material 30 is shown in FIG. 9, and is depicted in FIG. 10as it might be used in forming an open cell reinforcing core 31, with agypsum board veneer 13 adhered to one side of the reinforcing core 31 toform a lightweight composite panel 10″. FIG. 10 further shows theconcave areas on opposite sides of the corrugated material filled withan expanded foam 32, although the foam could be omitted if desired. Abacking sheet 33 may cover the side of the panel opposite the gypsumveneer.

[0051] Another alternative construction is shown in FIG. 11, whereinplural sheets 30 a and 30 b of corrugated material are arranged withtheir respective corrugations extending at a right angle to one another.The sheets of corrugated material may be used with or without anexpanded foam filling the spaces in the convolutions of the corrugatedmaterial.

[0052] A further alternative construction is shown in FIG. 12, wherein acombination of honeycomb 12 and corrugated 30 is laminated to form areinforcing core. Again, this construction may be used with or withoutan expanded foam filling the spaces in the core.

[0053] While particular embodiments of the invention have beenillustrated and described in detail herein, it should be understood thatvarious changes and modifications may be made to the invention withoutdeparting from the spirit and intent of the invention as defined by thescope of the appended claims

What is claimed is:
 1. A lightweight panel construction, comprising: athin sheet of gypsum board laminated as a facing sheet onto a backing oflightweight open cell reinforcing structure to form a lightweight butstrong composite panel as a substitute for gypsum board, said thin sheetof gypsum board having a thickness sufficient only to present anappearance and surface characteristics like that of a conventional sheetof gypsum board.
 2. A panel construction as claimed in claim 1, wherein:said composite panel has length, width and thickness dimensions the sameas conventional commercially available gypsum board.
 3. A panelconstruction as claimed in claim 1, wherein: said thin sheet of gypsumboard has a thickness of from about {fraction (1/16)} of an inch up toabout ¼ of an inch.
 4. A panel construction as claimed in claim 3,wherein: said sheet of gypsum board has a thickness of about {fraction(1/16)} of an inch, and the backing has a thickness of about {fraction(5/16)} of an inch, whereby the composite panel has a thickness of about⅜ of an inch.
 5. A panel construction as claimed in claim 3, wherein:said sheet of gypsum board has a thickness of about ⅛ of an inch, andthe backing has a thickness of about ¼ of an inch, whereby the compositepanel has a thickness of about ⅜ of an inch.
 6. A panel construction asclaimed in claim 3, wherein: said sheet of gypsum board has a thicknessof about {fraction (1/16)} of an inch, and the backing has a thicknessof about {fraction (11/16)} of an inch, whereby the composite panel hasa thickness of about ¾ of an inch.
 7. A panel construction as claimed inclaim 1, wherein: the open cell reinforcing structure comprises ahoneycomb structure with hexagonally shaped cells.
 8. A wallboardconstruction as claimed in claim 7, wherein: the honeycomb structure ismade of a paper material.
 9. A panel construction as claimed in claim 8,wherein: the cells of the honeycomb structure are filled with a foamedmaterial that further reinforces and rigidifies the structure and bondsthe components together.
 10. A panel construction as claimed in claim 1,wherein: the open cell reinforcing structure comprises a corrugatedstructure.
 11. A panel construction as claimed in claim 1, wherein: theopen cell reinforcing structure comprises a lamination of plural layersof corrugated material arranged with the convolutions thereof extendingat a right angle to one another.
 12. A panel construction as claimed inclaim 1, wherein: the open cell reinforcing structure comprises alamination formed of alternate layers of honeycomb and corrugatedmaterial.
 13. A panel construction comprising a lightweight, open cellreinforcing structure covered on at least one side with a thin veneer ofgypsum board to form a lightweight but strong composite panel that is asubstitute for conventional gypsum board, said veneer of gypsum boardhaving a thickness sufficient only to emulate the surface of aconventional sheet of gypsum board.
 14. A panel construction as claimedin claim 13, wherein: the open cell reinforcing structure comprises ahoneycomb configuration with hexagonally shaped cells.
 15. A panelconstruction as claimed in claim 13, wherein: the thin veneer of gypsumboard has a first thickness and the reinforcing structure has a secondthickness greater than the first thickness, the first and secondthicknesses combined being equivalent to the thickness of a conventionalgypsum board.
 16. A panel construction as claimed in claim 13, wherein:the open cell reinforcing structure is filled with an expanded foammaterial.
 17. A panel construction as claimed in claim 14, wherein: thecells of the honeycomb are filled with an expanded foam material.
 18. Apanel construction as claimed in claim 13, wherein: raceways or channelsfor utilities or the like are formed in the open cell reinforcingstructure.